During application of cancer chemotherapy, the bone marrow, the nerve tissues, the gastrointestinal mucosal cells, and the like are damaged due not only to the underlying disease but also to an influence of an adverse effect of the drug, and side effects such as bone marrow suppression, renal disorder, nausea, vomiting (anorexia), alopecia, and stomatitis develop (Non-Patent Document 1).
During application of cancer chemotherapy, because active oxygen attributable to a biological damage caused by the chemotherapy is produced in abundance, consumption of an antioxidant substance that captures the active oxygen thus produced is increased.
Also, while the required amount of zinc is increased to accommodate enhanced DNA synthesis and protein synthesis for repair of damaged tissues, the amount of urinary excretion of zinc is increased due to inflammation. Accordingly, it is important to supplement sufficient amounts of trace nutrients such as antioxidant vitamins and zinc.
However, because main side effects of cancer chemotherapy are anorexia, stomatitis, and vomiting, sufficient intake amounts cannot be secured, and therefore supplementation of trace nutrients cannot rely on a dietary source alone. Further, deficiency in trace nutrients such as zinc aggravates taste and olfaction disorder and delay in wound healing, with the potential risk for creating a vicious circle. It is important to implement a preventive measure against these side effects from the viewpoint of quality of life (QOL) as well.
Non-Patent Document 1: ITO, Akihiko, Japan J. Cancer Chemother 29(4), 2002